Perl XS: Memory management

Question

I am absolutely new to Perl XS.

My simple testfunction gets a string and appends something. In Perl is is a scalar-string in and one out.

In the function I have a malloc. Whats the correct way to free the mem?

SV *foo (str)
   SV *str
CODE:
    unsigned char *strbuf;
    size_t strlen;
    strbuf = (unsigned char *) SvPV (str, strlen);

    int n = strlen + 10;
    unsigned char *buf = malloc (n);    

    strncpy (buf, strbuf, strlen);
    strncat (buf, "0123456789", 10);

    RETVAL = newSVpv (buf, n);
OUTPUT:
    RETVAL

thanks! Chris

Answer 1

newSVpv creates an internal copy of the string, so you can simply free the memory by calling free after assigning to RETVAL.